A probe is sent to a star to see what bodies are orbiting the star. You need an observatory to build probes. If you're part of an alliance then your probes will be shared with other alliance members. Probes are single-use only, ie once they are sent to a star, they stay there indefinitely monitoring that system. There are no options to recall them.
The colour of a star has no significance. For looking at the orbiting body surfaces, you will need to send a scanner, surveyor, or use the Temple of the Drajilites.
Keywords: Observatory Ships